package com.dhz.common.web.utils;

import com.dhz.common.utils.security.EncoderUtils;
import com.google.common.base.Charsets;
import com.google.common.net.HttpHeaders;
import org.apache.commons.lang3.Validate;
import org.springframework.util.CollectionUtils;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

import javax.servlet.ServletRequest;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.*;
import java.util.Map.Entry;

/**
 * Http与Servlet工具类.
 */
public class Servlets {

    // -- 常用数值定义 --//
    public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365;

    /**
     * 设置客户端缓存过期时间 的Header.
     */
    public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) {
        // Http 1.0 header, set a fix expires date.
        response.setDateHeader(HttpHeaders.EXPIRES, System.currentTimeMillis() + (expiresSeconds * 1000));
        // Http 1.1 header, set a time after now.
        response.setHeader(HttpHeaders.CACHE_CONTROL, "private, max-age=" + expiresSeconds);
    }

    /**
     * 设置禁止客户端缓存的Header.
     */
    public static void setNoCacheHeader(HttpServletResponse response) {
        // Http 1.0 header
        response.setDateHeader(HttpHeaders.EXPIRES, 1L);
        response.addHeader(HttpHeaders.PRAGMA, "no-cache");
        // Http 1.1 header
        response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache, no-store, max-age=0");
    }

    /**
     * 设置LastModified Header.
     */
    public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) {
        response.setDateHeader(HttpHeaders.LAST_MODIFIED, lastModifiedDate);
    }

    /**
     * 设置Etag Header.
     */
    public static void setEtag(HttpServletResponse response, String etag) {
        response.setHeader(HttpHeaders.ETAG, etag);
    }

    /**
     * 根据浏览器If-Modified-Since Header, 计算文件是否已被修改.
     *
     * 如果无修改, checkIfModify返回false ,设置304 not modify status.
     *
     * @param lastModified 内容的最后修改时间.
     */
    public static boolean checkIfModifiedSince(HttpServletRequest request, HttpServletResponse response,
            long lastModified) {
        long ifModifiedSince = request.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE);
        if ((ifModifiedSince != -1) && (lastModified < (ifModifiedSince + 1000))) {
            response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
            return false;
        }
        return true;
    }

    /**
     * 根据浏览器 If-None-Match Header, 计算Etag是否已无效.
     *
     * 如果Etag有效, checkIfNoneMatch返回false, 设置304 not modify status.
     *
     * @param etag 内容的ETag.
     */
    public static boolean checkIfNoneMatchEtag(HttpServletRequest request, HttpServletResponse response, String etag) {
        String headerValue = request.getHeader(HttpHeaders.IF_NONE_MATCH);
        if (headerValue != null) {
            boolean conditionSatisfied = false;
            if (!"*".equals(headerValue)) {
                StringTokenizer commaTokenizer = new StringTokenizer(headerValue, ",");

                while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) {
                    String currentToken = commaTokenizer.nextToken();
                    if (currentToken.trim().equals(etag)) {
                        conditionSatisfied = true;
                    }
                }
            } else {
                conditionSatisfied = true;
            }

            if (conditionSatisfied) {
                response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                response.setHeader(HttpHeaders.ETAG, etag);
                return false;
            }
        }
        return true;
    }

    /**
     * 设置让浏览器弹出下载对话框的Header.
     *
     * @param fileName 下载后的文件名.
     */
    public static void setFileDownloadHeader(HttpServletRequest request, HttpServletResponse response, String fileName) {
        // 中文文件名支持
        String encodedfileName = null;
        // 替换空格，否则firefox下有空格文件名会被截断,其他浏览器会将空格替换成+号
        encodedfileName = fileName.trim().replaceAll(" ", "_");
        String agent = request.getHeader("User-Agent");
        boolean isMSIE = (agent != null && agent.toUpperCase().contains("MSIE"));
        if (isMSIE) {
            encodedfileName = EncoderUtils.urlEncode(fileName);
        } else {
            encodedfileName = new String(fileName.getBytes(), Charsets.ISO_8859_1);
        }

        response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + encodedfileName + "\"");

    }

    /**
     * 取得带相同前缀的Request Parameters, copy from spring WebUtils.
     *
     * 返回的结果的Parameter名已去除前缀.
     */
    @SuppressWarnings("rawtypes")
    public static Map<String, Object> getParametersStartingWith(ServletRequest request, String prefix) {
        Validate.notNull(request, "Request must not be null");
        Enumeration paramNames = request.getParameterNames();
        Map<String, Object> params = new TreeMap<String, Object>();
        if (prefix == null) {
            prefix = "";
        }
        while ((paramNames != null) && paramNames.hasMoreElements()) {
            String paramName = (String) paramNames.nextElement();
            if ("".equals(prefix) || paramName.startsWith(prefix)) {
                String unprefixed = paramName.substring(prefix.length());
                String[] values = request.getParameterValues(paramName);
                if ((values == null) || (values.length == 0)) {
                    // Do nothing, no values found at all.
                } else if (values.length > 1) {
                    params.put(unprefixed, values);
                } else {
                    params.put(unprefixed, values[0]);
                }
            }
        }
        return params;
    }

    /**
     * 组合Parameters生成Query String的Parameter部分, 并在paramter name上加上prefix.
     *
     * @see #getParametersStartingWith
     */
    public static String encodeParameterStringWithPrefix(Map<String, Object> params, String prefix) {
        if (CollectionUtils.isEmpty(params)) {
            return "";
        }

        if (prefix == null) {
            prefix = "";
        }

        StringBuilder queryStringBuilder = new StringBuilder();
        Iterator<Entry<String, Object>> it = params.entrySet().iterator();
        while (it.hasNext()) {
            Entry<String, Object> entry = it.next();
            queryStringBuilder.append(prefix).append(entry.getKey()).append('=').append(entry.getValue());
            if (it.hasNext()) {
                queryStringBuilder.append('&');
            }
        }
        return queryStringBuilder.toString();
    }

    /**
     * 从请求的request对象中获取cookie中指定属性的信息
     * @param request {@link HttpServletRequest}
     * @param key 参数名称
     * @return 返回参数值
     */
    public static String getCookie(HttpServletRequest request, String key) {
        if (null == request) {
            return null;
        }
        final Cookie[] cookies = request.getCookies();
        if (cookies == null) {
            return null;
        }
        String result = null;
        for (final Cookie cookie : cookies) {
            if (cookie.getName().equalsIgnoreCase(key)) {
                result = cookie.getValue();
                break;
            }
        }
        return result;
    }

    /**
     * 客户端对Http Basic验证的 Header进行编码.
     */
    public static String encodeHttpBasic(String userName, String password) {
        String encode = userName + ":" + password;
        return "Basic " + EncoderUtils.encodeBase64(encode.getBytes());
    }

    /**
     * 获取所有request请求参数key-value
     * 
     * @param request {@link HttpServletRequest}
     * @return 返回请求参数的key-value map对象
     */
    public static Map<String, String> getRequestParams(HttpServletRequest request){
        
        Map<String, String> params = new HashMap<String, String>();
        if(null != request){
            Set<String> paramsKey = request.getParameterMap().keySet();
            for(String key : paramsKey){
                params.put(key, request.getParameter(key));
            }
        }
        return params;
    }

    /**
     * 从Request对象中取出MultipartFiles数据
     * @param request  {@link HttpServletRequest}
     * @return {@link ArrayList} MultipartFile List
     */
    public static ArrayList<MultipartFile> getMultipartFiles (HttpServletRequest request) {
        ArrayList<MultipartFile> files = new ArrayList<MultipartFile>();
        // 设置上下方文
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(request.getSession().getServletContext());
        // 检查form是否有enctype="multipart/form-data"
        if (multipartResolver.isMultipart(request)) {
            MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;
            Iterator<String> iter = multiRequest.getFileNames();
            while (iter.hasNext()) {
                MultipartFile file = multiRequest.getFile(iter.next());
                if (file != null) {
                    files.add(file);
                }
            }
        }
        return files;
    }

}
